In recent years, organic electroluminescent display, as a new flat panel display, is getting more and more attention. The organic electroluminescent display features to lightness and thinness, wide viewing angle, low power consumption, fast response, flexible display, etc. Being an active light emitting, device, it is considered to have a great advantage in terms of high-definition and high-speed screen, and is making, progress toward a practical using direction recently. Core part of organic electroluminescent display is organic electroluminescent device, namely, OLED unit.
An organic film layer of the OLED unit in the organic electroluminescent device is easy to lose effectiveness because of suffering from water-oxygen corrosion, and therefore, it is required to be protected with a packaging structure for isolating from water-oxygen. Usually, hard packaging substrate (such as glass, metal sheet) with high water resistance performance is used in this field. That is to say, outside the OLED unit, two substrates for supporting the OLED unit are bonded via packaging adhesive, and an airtight space which water-oxygen is difficult to penetrate is formed between two substrates. This method can protect the OLED unit effectively, but is not suitable for flexible devices. Thus, there is a technical solution that a film having a certain water resistance performance is provided outside the OLED unit. But a dense film often has bad bendability, for example, SiOx film. Moreover, a film with good bendability has bad water resistance performance, for example, polymer film. There is also a technical solution that a multilayered film packaging structure is provided outside the OLED unit, in which multilayered organic films and inorganic films are alternately stacked to obtain better bendability and water resistance performance, but the multilayered film packaging structure has multiple layers, resulting in multisteps manufacturing process, costing long time, and depending on quality of film layers severely, especially the quality of inorganic film layers. A large area of inorganic film easily ruptures during bending, so as to form new water molecules corrosion pathway, thereby degrading the performance of the packaging structure.